The domain of the function y=√x-4 is restricted by the square root of a non-negative number, which means that x-4 must be greater than or equal to zero. Thus, we have:
x-4 ≥ 0
x ≥ 4
Therefore, the domain of the function is x≥4.
The range of the function is determined by the output values of the function. Since the square root of any non-negative number is always non-negative, the output values of the function y=√x-4 will always be non-negative. Thus, the range of the function is y≥0.
Therefore, the correct answer is A. Domain: x≥−4, Range: y≥0.